ASTM C1942-24

• Abstract:

  SIGNIFICANCE AND USE; 4.1 Some tile surfaces may exhibit variations under low angle conditions as part of the designed aesthetic. ; 4.2 This practice is intended for tiles that are designed to have an overall uniform appearance under low angle conditions.; SCOPE; 1.1 This practice replicates low angle viewing conditions on ceramic tile installations. ; 1.2 The values stated in inch-pound units are to be regarded as the standard. The values in parentheses are for information only. ; 1.3 This qualitative practice is intended to provide general guidance at the manufacturing level to determine if product will be acceptable under typical end use conditions. ; 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. ; 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

• Status: Published
• Publication Date: 31-Jan-2024
• Technical Committee: C21 - Ceramic Whitewares and Related Products
• Drafting Committee: C21.06 - Ceramic Tile

Overview

ASTM C1942-24: Standard Practice for Evaluation of Low Angle Light Characteristics provides a systematic method for replicating low angle viewing conditions on ceramic tile installations. Developed by ASTM International, this standard offers qualitative guidance at the manufacturing level to assess whether a tile product will present a uniform appearance under typical low angle lighting conditions. This evaluation is crucial for ensuring the expected visual quality and uniformity of ceramic tiles, particularly in spaces where aesthetic integrity under various lighting is essential.

Key Topics

• Low Angle Light Conditions: The standard defines these conditions as situations where horizontal tile surfaces are backlit and viewed at shallow angles (typically less than 45° with respect to the light source). Such viewing angles can reveal visual variations or defects not apparent under normal conditions.

• Visual Defects: The standard introduces the concept of "low angle light defects," which are variations or differences within or between tiles that are outside the product's intended aesthetic. Common issues can include checkerboard patterns from gloss differences or specific surface imperfections.

• Applicability: ASTM C1942-24 is intended for use with ceramic tiles designed to appear uniformly under low angle lighting. Some tiles may be intentionally designed for visual variation, in which case this practice serves to verify if the intended appearance is consistently achieved.

• Qualitative Assessment: The evaluation involves selecting random tile samples, arranging them in a controlled light box environment, and observing for visible defects or variations. The process includes recording tile details and documenting any observed issues with photographs.

Applications

This standard is especially valuable for:

• Ceramic Tile Manufacturers: Used during production to ensure products will meet end-user expectations and project specifications regarding visual appearance under low angle light.

• Quality Control Laboratories: Provides a standardized way to assess and document surface uniformity of ceramic tiles before products leave the factory.

• Project Managers and Specifiers: Offers a reliable reference for specifying acceptable uniformity and appearance standards in architectural and interior design projects, particularly in high-visibility areas with varied lighting.

• Installers and Inspectors: Helps verify that tile products delivered to a site match the intended appearance, reducing disputes and rework related to visual defects.

Related Standards

For comprehensive evaluation and specification of ceramic tile products, the following related ASTM standards may be consulted:

• ASTM F109 - Terminology Relating to Surface Imperfections on Ceramics: Provides definitions and discussions on types of surface defects and imperfections relevant to ceramic products.

• ASTM Standards on Ceramic Tiles: Covers testing methods, performance criteria, and other practices applicable to the production and use of ceramic tiles.

Practical Value

Adhering to ASTM C1942-24 ensures that ceramic tile installations will achieve the desired visual effect in spaces where low angle lighting may accentuate differences in gloss or surface quality. By following a uniform assessment protocol, manufacturers and project stakeholders can prevent unexpected visual variations, uphold quality standards, and minimize callbacks or complaints from end users.

Keywords

ceramic tile evaluation, low angle light, ASTM C1942-24, tile visual defects, surface uniformity, ceramic tile quality, lighting conditions, architectural specification, tile inspection, manufacturing quality control

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C1942 − 24
Standard Practice for
Evaluation of Low Angle Light Characteristics
This standard is issued under the fixed designation C1942; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.2 low angle light defect, n—a visual difference between
tiles, or within a tile, that is outside of the products intended
1.1 This practice replicates low angle viewing conditions on
aesthetic at lower angles (less than 45°).
ceramic tile installations.
3.1.2.1 Discussion—When viewed at near vertical condi-
1.2 The values stated in inch-pound units are to be regarded
tions (60° to 90°) the defect is typically not detectable. On
as the standard. The values in parentheses are for information
lower gloss tiles this can be a checkerboard pattern (gloss
only.
difference) from tile to tile as shown by Fig. 1. Higher gloss
(polished) tiles may exhibit specific defects under these con-
1.3 This qualitative practice is intended to provide general
ditions as described in Terminology F109.
guidance at the manufacturing level to determine if product
will be acceptable under typical end use conditions.
4. Significance and Use
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 4.1 Some tile surfaces may exhibit variations under low
responsibility of the user of this standard to establish appro-
angle conditions as part of the designed aesthetic.
priate safety, health, and environmental practices and deter-
4.2 This practice is intended for tiles that are designed to
mine the applicability of regulatory limitations prior to use.
have an overall uniform appearance under low angle condi-
1.5 This international standard was developed in accor-
tions.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
5. Apparatus
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
5.1 Any viewing box that controls the lighting conditions
Barriers to Trade (TBT) Committee. and fixes the visible angle available to the evaluator.
5.2 The box shall be wide enough to accommodate at least
2. Referenced Documents
two tiles being viewed, so length and width may vary. An
2.1 ASTM Standards: opening of 6.0 in. 6 1.0 in. (127 mm to 177.8 mm) that per-
F109 Terminology Relating to Surface Imperfections on
mits viewing of the product without directly observing the light
Ceramics source. An example is provided as Fig. 2.
5.3 The light source shall be placed a minimum of 12 in.
3. Terminology
behind the rear edge of the tile in relation to the front of the
3.1 Definitions:
box.
3.1.1 low angle light conditions, n—conditions of where a
5.4 Light Source, of sufficient strength to cast a strong
horizontal surface is back lit and the viewing angle is very
diffused, light across the samples from the rear of the box. An
shallow with respect to the light source. Typically less than
18W LED 24 in. fixture with 1350 lm and a color temperature
45°.
of 5000 K was found to be sufficient for a 50 in. by 60 in. by
6 in. box shown in Fig. 2.
This practice is under the jurisdiction of ASTM Committee C21 on Ceramic
6. Test Specimens
Whitewares and Related Products and is the direct responsibility
...